Transmission with electronic range selector and pull out of park control logic

ABSTRACT

A vehicle includes a transmission, and an Electronic Transmission Range Selection (ETRS) system. The transmission has a plurality of clutches, a park pawl, and a park sensor. The ETRS system has a controller and an electronic range selector device. The controller is programmed to detect a delay in pull out of the park pawl from a park position and to control an action of the vehicle in response to the delay by receiving an electronic range request signal to shift from a park operating range to another operating range; receiving a park pawl position signal from the park sensor; determining if pull out of the park pawl from the park position has not occurred by a predetermined time; and increasing one of a line pressure, a clutch pressure, and an idle speed if pull out of the park pawl from the park position has not occurred by the predetermined time.

TECHNICAL FIELD

The present disclosure relates to a transmission having an electronicrange selector and pull out of park control logic.

BACKGROUND

A conventional automatic vehicle transmission includes a shift leverpositioned in a vehicle interior in easy reach of a driver of thevehicle. Movement of the shift lever enables the driver to manuallyselect a desired transmission operating range, usually from park,reverse, neutral, drive, and first gear/low. This lever, which isreferred to as a PRNDL lever in the art, is mechanically coupled to ashift valve of the transmission by a length of cable. Tension on thecable during actuation of the shift lever moves the shift valve tothereby enable the selected operating range.

An Electronic Transmission Range Select (ETRS) system may be used as analternative to a mechanically-actuated PRNDL lever. An ETRS systemdispenses with the cable in favor of transmitting electronic signals,either to the shift valve or to flow/pressure control solenoidsdepending on the design. ETRS systems thus enable by-wire rangeselection, which can help to reduce weight while providing otherperformance advantages.

As is well known in the art, transmission park systems typically engagea park gear using a park pawl. The park gear is connected to atransmission output member. Thus, whenever the driver shifts thetransmission into park, the park pawl is moved into a park position andteeth or splines of the park pawl engage mating teeth or splines of thepark gear to prevent rotation of the output member. When the drivershifts the transmission out of park, the park pawl is pulled out of thepark position and the teeth or splines of the park pawl disengage fromthe mating teeth or splines of the park gear to enable rotation of theoutput member. Pull out of the park pawl from the park position may beachieved by pulling, pushing, or torquing the park pawl to move it fromthe park position.

When the transmission of a vehicle with an ETRS system is shifted fromthe park operating range to another operating range, a delay in pull outof the park pawl from the park position may occur. The delay may becaused by a lack of sufficient force to move the park pawl from the parkposition due to insufficient hydraulic pressure, loading of the parkpawl, for example when the vehicle is parked on a grade, or othervehicle and transmission conditions. In some circumstances, it may notbe possible to remove the park pawl from the park position, even after adelay.

SUMMARY

A vehicle is disclosed herein having an engine, a transmission, and anElectronic Transmission Range Selection (ETRS) system. The engine has anidle speed. The transmission is connected to the engine and has ahydraulic pressure source, a plurality of clutches, a shift valve, apark pawl, and a park sensor. The hydraulic pressure source supplieshydraulic fluid at line pressure. The clutches each have a respectiveclutch pressure. The shift valve, which is in fluid communication withthe hydraulic pressure source and the plurality of clutches, is operableto shift the transmission to a requested operating range via theplurality of clutches. The park pawl is pulled out of a park position toshift the transmission out of a park operating range via one or more ofthe clutches when the transmission is requested to shift from the parkoperating range to another operating range. The park sensor isconfigured to determine if the park pawl is pulled out of the parkposition. The ETRS system has a controller and an electronic rangeselector device. The electronic range selector device is operable totransmit an electronic range request signal to the controller to requesta shift of the transmission to the requested operating range.

The controller is programmed to detect a delay in pull out of the parkpawl from the park position when the transmission is requested to shiftfrom the park operating range to another operating range. The controlleris also programmed to control an action of the vehicle in response tothe delay by receiving the electronic range request signal to shift fromthe park operating range to another operating range from the electronicrange selector device. Additionally, the controller receives a park pawlposition signal from the park sensor indicative of the park pawl beingpulled out of the park position, determines if pull out of the park pawlfrom the park position has not occurred by a predetermined time afterthe range request signal has been received, and increases the linepressure, the clutch pressures, and/or the idle speed if pull out of thepark pawl from the park position has not occurred by the predeterminedtime.

A system for use in a vehicle having an engine and a transmission isalso disclosed herein. The system includes a hydraulic pressure source,a plurality of clutches, a shift valve, a park pawl, a park pawl sensor,and an Electronic Transmission Range Selection (ETRS) system. Thehydraulic pressure source supplies hydraulic fluid at line pressure. Theclutches each have a respective clutch pressure. The shift valve is influid communication with the hydraulic pressure source and the pluralityof clutches, and is operable to shift the transmission to a requestedoperating range via the plurality of clutches. The park pawl is pulledout of a park position to shift the transmission out of a park operatingrange via one or more of the clutches when the transmission is requestedto shift from the park operating range to another operating range. Thepark sensor is configured to determine if the park pawl is pulled out ofthe park position. The ETRS system has a controller and an electronicrange selector device. The electronic range selector device is operableto transmit an electronic range request signal to the controller torequest the shift of the transmission to the requested operating range.

The controller is in communication with the electronic transmissionrange selection system and the park sensor. The controller is programmedto receive the electronic range request signal to shift from the parkoperating range to another operating range from the electronic rangeselector device, and to receive a park pawl position signal from thepark sensor indicative of the park pawl being pulled out of the parkposition. The controller also determines if pull out of the park pawlfrom the park position has not occurred by a predetermined time afterthe range request signal has been received, and increases the linepressure, the clutch pressures, and/or an idle speed of the engine ifpull out of the park pawl from the park position has not occurred by thepredetermined time.

An example method is also disclosed herein. The method is forcontrolling a vehicle having a transmission and an ElectronicTransmission Range Selection (ETRS) system in response to a delay inpull out of a park pawl from a park position when a shift from a parkoperating range to another operating range is requested. The methodincludes receiving, via a controller, an electronic range request signalfrom an electronic range selector device, sending a pull out of parksignal to a shift valve of the transmission, and receiving, via thecontroller, a park pawl position signal from a park sensor. The methodalso includes determining, via the controller, if a park pawl is notpulled out a park position by a predetermined time after the electronicrange request signal has been received, and executing a control actionwith respect to the vehicle when the park pawl has not been pulled outthe park position by the predetermined time. The control action mayinclude increasing a line pressure, a clutch pressure, and/or an idlespeed.

The vehicle, system, and method disclosed herein detect a delay in pullout of the park pawl from the park position in a vehicle with an ETRSsystem and take pre-emptive actions that may allow the driver to shiftout of the park operating range to another operating range with littleor no delay.

The above features and advantages and other features and advantages ofthe present teachings are readily apparent from the following detaileddescription of the best modes for carrying out the present teachingswhen taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a vehicle having an ElectronicTransmission Range Selection (ETRS) system controlled during a pull outof park event as set forth herein.

FIG. 2 is an example time plot of hydraulic pressure, rotational speed,and electronic signal parameters of the vehicle shown in FIG. 1 during anormal pull out of park event, with time plotted on the horizontal axisand hydraulic pressure, rotational speed, and electronic signalparameters plotted on the vertical axis.

FIG. 3 is an example time plot of hydraulic pressure, rotational speed,and electronic signal parameters of the vehicle shown in FIG. 1 during adelayed pull out of park event without the control as set forth herein,with time plotted on the horizontal axis and hydraulic pressure,rotational speed, and electronic signal parameters plotted on thevertical axis.

FIG. 4 is an example time plot of hydraulic pressure, rotational speed,and electronic signal parameters of the vehicle shown in FIG. 1 during apotentially delayed pull out of park event with the pull out of parkevent controlled as set forth herein, with time plotted on thehorizontal axis and hydraulic pressure, rotational speed, and electronicsignal parameters plotted on the vertical axis.

FIG. 5 is a flowchart showing an example method of controlling the ETRSsystem of the vehicle shown in FIG. 1 during a pull out of park event.

DETAILED DESCRIPTION

Referring to the drawings, an example vehicle 10 is shown schematicallyin FIG. 1 having an internal combustion engine 12 and an automatictransmission 14 connected to the engine 12. The engine 12 has an idlespeed V_(I). The vehicle 10 is equipped with an Electronic TransmissionRange Selection (ETRS) system 16 that is operable for commanding a rangeshift of the transmission 14, electronically/by-wire, into a desiredoperating range. Such a range typically includes park (P), reverse (R),neutral (N), drive (D), and 1^(st) gear/low (L), i.e., the conventionalPRNDL range.

The ETRS system 16 includes an electronic range selector device 18 and acontroller 20. The electronic range selector device 18 is operable totransmit an electronic range request signal (arrow 28) to the controller20 to request a shift of the transmission 14 to the requested operatingrange. The controller 20 is configured, i.e., equipped in hardware andprogrammed in software, to execute instructions embodying a method 100,an example of which is provided in FIG. 5 and described below withreference to FIG. 5. Execution of the method 100 ultimately controls apull out of park operation of the vehicle 10 and provides drivernotification when necessary. The method 100 helps to ensure that a parkpawl 22 of the transmission 14 is pulled out of a park position withlittle or no delay.

The electronic range selector device 18 may include a plurality ofpush-buttons 24. Each push-button 24 corresponds to a desired operatingrange of the transmission, e.g., separate push-buttons 24 for park (P),reverse (R), neutral (N), drive (D), and 1^(st) gear/low (L). The term“push-button” applies herein to any suitable by-wire actuated input,whether embodied as spring-biased buttons, as icons displayed on atouch-sensitive electronic display, as a shift lever, or otherwise.

Key to the present approach is that the electronic range selector device18 is not mechanically connected to a shift valve 26. Instead, adepression of one of the push-buttons 24 causes a transmission of theelectronic range selection signal 28 to the controller 20, whichreceives the transmitted range selection signal (arrow 28) and commandsa shift of the transmission 14 to the corresponding operating range. Theoperating range is commanded via transmission of a shift control signal(arrow 30) to the shift valve 26 or to multiple solenoids or other flowor pressure control valves located in the transmission 14, depending onthe embodiment.

With further reference to the structure of the example vehicle 10 asshown in FIG. 1, the engine 12 includes an output shaft 32 that rotatesat engine speed. The engine speed may be the idle speed V_(I), as shown.A hydrodynamic torque converter 34 is connected to the output shaft 32,as well as to an input member 36 of the transmission 14. The inputmember 36 rotates at a transmission input speed (arrow V_(T)). As isknown in the art, the torque converter 34 provides desiredmultiplication of torque from the engine 12 into the transmission 14 atlow speeds. Other embodiments of the vehicle 10 may use a clutch orclutch and damper assembly in lieu of the torque converter 34 withoutdeparting from the intended inventive scope. Likewise, the powertrain ofthe vehicle 10 may include one or more electric traction motors in anoptional hybrid embodiment to provide additional sources of inputtorque.

The transmission 14 also includes an output member 38 that deliversoutput torque (arrow TQ) to one or more drive axles 40, and ultimatelyto a set of drive wheels 42. As is well known in the art, transmissionpark systems typically engage a park gear, not shown, using a park pawl22. Although the park pawl 22 is shown schematically for illustrativesimplicity, those of ordinary skill in the art will recognize that sucha device has teeth or splines (not shown) that mate with teeth orsplines of a park gear (not shown) of the transmission 14. The park gearis connected to the transmission output member 38. Thus, whenever adriver shifts the transmission 14 into a park operating range, the parkpawl 22 is moved into a park position and teeth or splines of the parkpawl (not shown) engage mating teeth or splines of the park gear (notshown) to prevent rotation of the output member 38. When the drivershifts the transmission 14 out of the park operating range, the parkpawl 22 is pulled out of the park position and teeth or splines of thepark pawl disengage from the mating teeth or splines of the park gear toenable rotation of the output member 38. Pull out of the park pawl 22from the park position is defined as pulling, pushing, or torquing thepark pawl 22 to move it out of the park position.

The controller 20 of FIG. 1 may be embodied as a computer device, ormultiple such devices, each having one or more processors 44 and memory46. The memory 46 includes sufficient amounts of tangible,non-transitory memory, e.g., optical or magnetic read only memory (ROM),erasable electrically-programmable read only memory (EEPROM), flashmemory, and the like, as well as transient memory such as random accessmemory (RAM). Although omitted for clarity, the controller 20 alsoincludes a high-speed clock, analog-to-digital (A/D) circuitry,digital-to-analog (D/A) circuitry, any required input/output (I/O)circuitry and devices, and signal conditioning/buffering/filteringelectronics.

Individual control algorithms resident in the controller 20 or readilyaccessible thereby, such as instructions embodying the method 100 ofFIG. 5, may be stored in memory 46 and automatically executed via theprocessor 44 to provide the respective control functionality. Possiblecontrol actions resulting from execution of the method 100 are describedin detail below.

The transmission 14 includes a hydraulic pressure source 48, a pluralityof clutches 54, the shift valve 26, the park pawl 22, and a park sensor50. The hydraulic pressure source 48 supplies hydraulic fluid 52 at linepressure P_(L). The plurality of clutches 54 each have respective clutchpressures P_(CL). The shift valve 26 is in fluid communication with thehydraulic pressure source 48 and the plurality of clutches 54 and isoperable to shift the transmission 14 to a requested operating range viathe plurality of clutches 54. The park pawl 22 is pulled out of a parkposition to shift the transmission 14 out of a park operating range viaone or more of the clutches 54 when the transmission 14 is requested toshift from the park operating range to another operating range. The parksensor 50 is operable to determine if the park pawl 22 is pulled out ofthe park position. The park sensor 50 sends a park pawl position signal(arrow 56) to the controller 20. The park sensor 50 may be a Hall Effectsensor or may be any other suitable sensor for determining if the parkpawl 22 is pulled out of the park position.

Referring now to FIG. 2, a first schematic time plot 78 shows a normalpull out of the park and garage shift operation of the ETRS system 16,i.e., a shift from the park operating range to a drive, low, or reverseoperating range. The time plot 78 includes both a pull out of parkoperation, defined as removal of the park pawl 22 of FIG. 1 from thepark position and a garage shift, defined as shifting of thetransmission 14 from the park operating range into a drive, low, orreverse operating range. Time t is schematically depicted on thehorizontal axis. Hydraulic pressure P, rotational speed V, andelectronic signal S parameters are schematically depicted on thevertical axis. In particular, the time plot 78 schematically plots linepressure P_(L), clutch pressures P_(CL), engine output shaft 32 idlespeed V_(I), transmission input shaft 36 speed V_(T), and park pawlposition signal 56 versus time t.

At a start or zero time t₀, the driver requests a shift from the parkoperating range to another operating range by providing an input to theelectronic range selector device 18 of FIG. 1. At t₀, the engine outputshaft 32 and the transmission input shaft 36 are both at idle speedV_(I), the hydraulic fluid 52 at the hydraulic pressure source 48 is atline pressure P_(L), the clutch pressures P_(CL) are at zero or lowpressure, and the park pawl position signal 56 indicates that the parkpawl 22 is in the park position. For example, at t₀ the idle speed V_(I)may be 500 rpm, line pressure P_(L) may be 800 kPa, clutch pressuresP_(CL) may be zero, and the park pawl position sensor 56 may indicatezero volts. Other speeds, pressures, and electronic signals are possibledepending on the specific embodiment.

At t₁, the clutch pressures P_(CL) begin to build up. As an example, thetime between t₀ and t₁ may be 50 ms. Other times are possible dependingon the specific embodiment. At pull out of park time t₂, the clutchpressure P_(CL) is sufficient to remove the park pawl 22 from the parkposition, and the park pawl position signal 56 indicates that the parkpawl 22 is out of the park position. For example, the time between t₂and t₁ may be 150 ms, the clutch pressures P_(CL) may rise to 800 kPa,and the park pawl position signal 56 may indicate a voltage greater thanzero. Thus, the overall pull out of park time between t₀ and t₂ may be200 ms. Other times, pressures, and electronic signals are possibledepending on the specific embodiment.

At t₃, an inertia phase of the garage shift begins. The garage shiftinertia phase is completed by garage shift complete time t₄. Between t₃and t₄, the transmission input shaft 36 speed V_(T) decreases from idlespeed V_(I) to zero or near zero rpm. As an example, the time between t₀and t₃ may be 500 ms, and the time between t₃ and t₄ may be 500 ms.Thus, the overall pull out of park and garage shift operation timebetween t₀ and t₄ may be a total of 1000 ms. Other times are possibledepending on the specific embodiment.

Referring now to FIG. 3, a second schematic time plot 80 shows a delayedpull out of park and garage shift operation of the ETRS system 16. As inFIG. 2, time t is schematically depicted on the horizontal axis.Hydraulic pressure P, rotational speed V, and electronic signal Sparameters are schematically depicted on the vertical axis. Inparticular, the time plot 80 schematically plots line pressure P_(L),clutch pressures P_(CL), engine output shaft 32 idle speed V_(I),transmission input shaft 36 speed V_(T), and park pawl position signal56 versus time t.

At start time t₀, the driver requests a shift from the park operatingrange to another operating range by providing an input to the electronicrange selector device 18 of FIG. 1. At t₀, the engine output shaft 32and the transmission input shaft 36 are both at idle speed V_(I), thehydraulic fluid 52 at the hydraulic pressure source 48 is at linepressure P_(L), the clutch pressures P_(CL) are at zero or a lowpressure, and the park pawl position signal 56 indicates that the parkpawl 22 is in the park position. As an example, at t₀ the idle speedV_(I) may be 500 rpm, line pressure P_(L) may be 800 kPa, clutchpressures P_(CL) may be zero kPa, and the park pawl position sensor 56may indicate zero volts. Other speeds, pressures, and electronic signalsare possible depending on the specific embodiment.

At t₁, the clutch pressures P_(CL) begin to build up. For example, thetime between t₀ and t₁ may be 50 ms. Other times are possible dependingon the specific embodiment. However, in this case, the clutch pressuresP_(CL) are not sufficient to remove the park pawl 22 from the parkposition, and the park pawl position signal 56 continues to indicatethat the park pawl 22 is in the park position. This delay in the pullout of park operation may be caused by a lack of sufficient force toremove the park pawl 22 from the park position resulting frominsufficient hydraulic pressure, loading of the park pawl 22, forexample when the vehicle 10 is parked on a grade, or other vehicle 10and transmission 14 conditions.

At t₃, the inertia phase of the garage shift begins. The garage shiftinertia phase is completed by garage shift complete time t₄. Between t₃and t₄, the transmission input shaft 36 speed V_(T) decreases from idlespeed V_(I) to zero or near zero rpm. For example, the time between t₀and t₃ may be 500 ms, the time between t₃ and t₄ may be 500 ms. Othertimes are possible depending on the specific embodiment.

The park pawl 22 may be pulled out of the park position at t₂, after thegarage shift is complete at t₄, as shown. As an example, the timebetween t₂ and t₀ may be 1150 ms or longer. Thus, the overall pull outof park and garage shift operation time may be delayed by 150 ms or moreto a total of 1150 ms or longer. Alternatively, there may never beenough force to pull the park pawl 22 out of the park position and theoutput member 38 may be prevented from rotating. Other times, pressures,and electronic signals are possible depending on the specificembodiment.

Referring now to FIG. 4, a third schematic time plot 82 shows an examplepull out of park and garage shift operation of the ETRS system 16 duringa delayed pull out of park event with the pull out of park eventcontrolled as set forth herein. As in FIGS. 2 and 3, time t isschematically depicted on the horizontal axis. Hydraulic pressure P,rotational speed V, and electronic signal S parameters are schematicallydepicted on the vertical axis. In particular, the time plot 82schematically plots line pressure P_(L), clutch pressures P_(CL), engineoutput shaft 32 idle speed V_(I), transmission input shaft 36 speedV_(T), and park pawl position signal 56 versus time t.

At start time t₀, the driver requests a shift from the park operatingrange to another operating range by providing an input to the electronicrange selector device 18 of FIG. 1. At t₀, the engine output shaft 32and the transmission input shaft 36 are both at idle speed V_(I), thehydraulic fluid 52 at the hydraulic pressure source 48 is at linepressure P_(L), the clutch pressures P_(CL) are at zero kPa or at a lowpressure, and the park pawl position signal 56 indicates that the parkpawl 22 is in the park position. For example, at t₀ the idle speed V_(I)may be 500 rpm, line pressure P_(L) may be 800 kPa, clutch pressuresP_(CL) may be zero kPa, and the park pawl position sensor 56 mayindicate zero volts. Other speeds, pressures, and electronic signals arepossible depending on the specific embodiment.

At t₁, the clutch pressure P_(CL) begins to build up. For example, thetime between t₀ and t₁ may be 50 ms. Other times are possible dependingon the specific embodiment. In this case, a delay in pull out of thepark pawl 22 from the park position occurs. However, at a calibration orpredetermined time t_(C) the delay in pull out of the park pawl 22 fromthe park position is detected and mitigation of the delay throughcontrol actions taken by the controller 20 begins. In this example, idlespeed V_(I), line pressure P_(L), and clutch pressures P_(CL) areincreased by the controller 20. For example, the time between thecalibration time t_(C) and the time t₀ may be 200 ms, the idle speedV_(I) may be increased to 800 rpm, the line pressure P_(L) may beincreased to 1,200 kPa, and the clutch pressures P_(CL) may be increasedto 1,200 kPa. Other times, pressures, and signals are possible dependingon the specific embodiment. In other embodiments, fewer, more, and/ordifferent control actions may be commanded by the controller 20.

At pull out of park time t₂, the clutch pressures P_(CL) are sufficientto remove the park pawl 22 from the park position, and the park pawlposition signal 56 indicates that the park pawl 22 is out of the parkposition. As an example, the time between the time t₂ and thecalibration time t_(C) may be 100 ms. Thus, the overall pull out of parkoperation time between t₀ and t₂ may thus be 300 ms. Other times,pressures, and electronic signals are possible depending on the specificembodiment.

At t₃, the inertia phase of the garage shift begins. The garage shiftinertia phase is completed by garage shift complete time t₄. Between t₃and t₄, the transmission input shaft 36 speed V_(T) decreases from idlespeed V_(I) to zero or near zero rpm. As an example, the time between t₀and t₃ may be 500 ms, and the time between t₃ and t₄ may be 500 ms.Thus, the overall pull out of park and garage shift operation timebetween t₀ and t₄ may not be delayed at a total of 1000 ms. Other timesare possible depending on the specific embodiment.

Referring again to FIG. 1, the controller 20 is programmed to detect adelay in pull out of the park pawl 22 from the park position when thetransmission 14 is requested to shift from the park operating range toanother operating range and to control an action of the vehicle 10 inresponse to the delay. The controller 20 accomplishes this by receivingthe electronic range request signal 28 to shift from the park operatingrange to another operating range from the electronic range selectordevice 18. The controller 20 also receives a park pawl position signal56 from the park sensor 50, determines if pull out of the park pawl 22from the park position has not occurred by a predetermined orcalibration time t_(C) after the range request signal 28 has beenreceived, and increases one of the line pressure P_(L), the clutchpressures P_(CL), and the idle speed V_(I) if pull out of the park pawl22 from the park position has not occurred by the predetermined timet_(C). The controller 20 may send an idle speed signal (arrow 72) to theengine 12 to increase the idle speed V_(I). The controller 20 may send aline pressure signal (arrow 74) to the hydraulic pressure source 48 orto solenoids or other flow or pressure control valves (not shown)located in the transmission 14 to increase the line pressure P_(L). Thecontroller 20 may also send a clutch pressure signal (arrow 76) to theone or more clutch solenoids or other flow or pressure control valves(not shown) located in the transmission 14 to increase the one or moreof the clutch pressures P_(CL).

The vehicle 10 may include a grade sensor 58 configured to detect anupgrade and a downgrade relative to the vehicle direction. Vehicledirection is defined as the direction for forward travel of the vehicle10 when the vehicle 10 is in the drive operating range. The controller20 may be programmed to receive an electronic grade signal 60 from thegrade sensor 58 to determine if the upgrade exceeds a predeterminedupgrade and the downgrade exceeds a predetermined downgrade. Thecontroller may also increase one of the line pressure P_(L), the clutchpressures P_(CL), and the idle speed V_(I) when one of the predeterminedupgrade and the predetermined downgrade is detected and when theelectronic range request signal 28 to shift from the park operatingrange to another operating range is received from the electronic rangeselector device 18.

The controller 20 of FIG. 1 may be programmed to increase one of theline pressure P_(L), the clutch pressures P_(CL), and the idle speedV_(I) when the electronic range request signal 28 to shift from the parkoperating range to another operating range is received from theelectronic range selector device 18 and pull out of the park pawl 22from the park position did not occur by the predetermined time t_(C) ina previous shift from the park operating range to another operatingrange.

The vehicle 10 may include a brake 62 having a brake sensor 64configured to determine if the brake 62 is applied. The brake sensor 64may detect a brake hydraulic pressure, a brake position, or any othersuitable measure of brake application. The controller 20 may beprogrammed to receive a brake application signal (arrow 66) from thebrake sensor 64 and to increase one of the line pressure P_(L), theclutch pressures P_(CL), and the idle speed V_(I) and to apply a driveoperating range when the electronic range request signal 28 to shiftfrom the park operating range to the drive operating range is receivedfrom the electronic range selector device 18, the upgrade exceeds thepredetermined upgrade, and the brake 52 is applied. The controller 10may be programmed to increase one of the line pressure P_(L), the clutchpressures P_(CL), and the idle speed V_(I) and to apply a reverseoperating range when the electronic range request signal 28 to shiftfrom the park operating range to the reverse operating range is receivedfrom the electronic range selector device 18, the downgrade exceeds thepredetermined downgrade, and the brake 62 is applied.

The controller 20 may be programmed to return the transmission 14 to thepark operating range if pull out of the park pawl 22 from the parkposition has not occurred by the predetermined time t_(C) afterincreasing one of the line pressure P_(L), the clutch pressures P_(CL),and the idle speed V_(I).

The vehicle 10 may include an indicator device 68. The controller 20 maybe programmed to transmit an indicator signal (arrow 70) to theindicator device 68 if pull out of the park pawl 22 from the parkposition has not occurred by the predetermined time t_(C) afterincreasing one of the line pressure P_(L), the clutch pressures P_(CL),and the idle speed V_(I). The controller 20 may be programmed to returnthe transmission 14 to the park operating range and to transmit anindicator signal 70 to the indicator device 68 if pull out of the parkpawl 22 from the park position has not occurred by the predeterminedtime t_(C) after increasing one of the line pressure P_(L), the clutchpressures P_(CL), and the idle speed V_(I) and applying one of the driveoperating range and the reverse operating range. The indicator device 68may include any one or more of a driver information center, a displayscreen, an audio speaker, and an indicator lamp depending on theembodiment.

FIG. 5 illustrates an example embodiment of the method 100 of FIG. 1.The method 100 is suitable for controlling the vehicle 10 of FIG. 1having the transmission 14 and the ETRS system 16 in response to a delayin pull out of the park pawl 22 from the park position when a shift fromthe park operating range to another operating range is requested.

Referring now to FIGS. 1 and 5, the method 100 begins with step 102,which includes receiving, via the controller 20 of FIG. 1, theelectronic range request signal 28 from the electronic range selectordevice 18. At step 104, the method 100 may include receiving, via thecontroller 20, the grade signal 60 from the grade sensor 58 of FIG. 1.At step 106, the method 100 may include determining, via the controller20, if a grade exceeds one of a predetermined upgrade and apredetermined downgrade. If the grade does not exceed one of thepredetermined upgrade and the predetermined downgrade, the method 100may proceed to step 108, to be described below. If the grade exceeds oneof the predetermined upgrade and the predetermined downgrade, the method100 may proceed to step 116, to be described below.

At step 108, the method 100 may include determining, via the controller20 of FIG. 1, if the park pawl 22 was not pulled out of the parkposition by a predetermined time t_(C) after the electronic rangerequest signal 28 was received in a previous shift from the parkoperating range to another operating range. If the park pawl 22 waspulled out of the park position by the predetermined time t_(C) afterthe electronic range request signal 28 was received in the previousshift from the park operating range to another operating range, themethod 100 may proceed to step 110, to be described below. If the parkpawl 22 was not pulled out of the park position by the predeterminedtime t_(C) after the electronic range request signal 28 was received inthe previous shift from the park operating range to another operatingrange, the method 100 may proceed to step 116, as described below.

At step 110, the method 100 includes sending the pull out of park signal30 to the shift valve 26 of the transmission 14 of FIG. 1. At step 112,the method 100 includes receiving, via the controller 20, the park pawlposition signal 56 from the park sensor 50. At step 114, the method 100includes determining, via the controller 20, if the park pawl 22 is notpulled out the park position by a predetermined time t_(C) after theelectronic range request signal 28 has been received. If the park pawl22 is not pulled out of the park position by the predetermined timet_(C) after the electronic range request signal 28 has been received,the method 100 proceeds to step 116, to be described below. If the parkpawl 22 is pulled out the park position by the predetermined time t_(C)after the electronic range request signal 28 has been received, themethod proceeds to step 118. At step 118, the method 100 includessending the garage shift signal 30 to the shift valve 26 of thetransmission 14. If the method 100 reaches step 118, the method 100 mayend. At this point, the pull out of park and garage shift operations arecomplete.

As described above, if the grade exceeds one of a predetermined upgradeand a predetermined downgrade at step 106, if the park pawl 22 was notpulled out of the park position by the predetermined time t_(C) afterthe electronic range request signal 28 was received in a previous shiftfrom the park operating range to another operating range at step 108, orif the park pawl 22 is not pulled out the park position by thepredetermined time t_(C) after the electronic range request signal 28has been received, at step 114 the method 100 may proceed to step 116.At step 116, the method 100 includes executing a first control actionwith respect to the vehicle 10. The first control action of step 116 mayinclude increasing one of the line pressure P_(L), the clutch pressuresP_(CL), and the idle speed V_(I) of the engine 12.

After step 116, the method 100 may proceed to step 110, sending the pullout of park signal 30 to the shift valve 26 of the transmission 14, andthen to step 114, determining, via the controller 20, if the park pawl22 is not pulled out the park position by the predetermined time t_(C)after the electronic range request signal 28 has been received. If thepark pawl 22 is not pulled out of the park position by the predeterminedtime t_(C) after the electronic range request signal 28 has beenreceived, the method 100 may proceed to step 122, as described below. Ifthe park pawl 22 is pulled out the park position by the predeterminedtime t_(C) after the electronic range request signal 28 has beenreceived, then the method proceeds to step 118, sending the garage shiftsignal 30 to the shift valve 26 of the transmission 14. If the method100 reaches step 118, the method 100 may end. At this point, the pullout of park and garage shift operations are complete.

The method may include step 120, which includes receiving, via thecontroller 20 of FIG. 1, the brake application signal 66 from the brakeapplication sensor 64 for the brake 62. The method 100 may include step122, which includes determining, via the controller 20, if theelectronic range request signal 28 to shift from the park operatingrange to a drive operating range is received from the electronic rangeselector device 18, the upgrade exceeds the predetermined upgrade, andthe brake 62 is applied. If the electronic range request signal 28 toshift from the park operating range to the drive operating range isreceived from the electronic range selector device 18, the upgradeexceeds the predetermined upgrade, and the brake 62 is applied, themethod 100 may proceed to step 124, as described below. If not, themethod 100 may proceed to step 126. The predetermined upgrade of step122 may be either the same as or different from the predeterminedupgrade of step 106.

At step 126, the method may include determining, via the controller 20,if the electronic range request signal 28 to shift from the parkoperating range to a reverse operating range is received from theelectronic range selector device 18, the downgrade exceeds thepredetermined downgrade, and the brake 62 is applied. If the electronicrange request signal 28 to shift from the park operating range to thereverse operating range is received from the electronic range selectordevice 18, the downgrade exceeds the predetermined downgrade, and thebrake 62 is applied, the method 100 may proceed to step 128, asdescribed below. If not, the method 100 may proceed to step 130, asdescribed below. The predetermined downgrade of step 126 may be the sameas or different from the predetermined downgrade of step 106.

At step 124, the method 100 may include executing a second controlaction. The second control action may include increasing one of a linepressure P_(L), the clutch pressures P_(CL), and the engine idle speedV_(I) and applying the drive operating range. At step 128, the method100 may include executing a third control action. The third controlaction may include increasing one of the line pressure P_(L), the clutchpressures P_(CL), and the engine idle speed V_(I) and applying thereverse operating range. After one of step 124 and step 128, the method100 may proceed to step 110, sending the pull out of park signal 30 tothe shift valve 26 of the transmission 14. After step 110, the method100 may proceed to step 114, determining, via the controller 20, if thepark pawl 22 is not pulled out of the park position by the predeterminedtime t_(C) after the electronic range request signal 28 has beenreceived. If the park pawl 22 is not pulled out the park position by thepredetermined time t_(C) after the electronic range request signal 28has been received, the method 100 may proceed to step 130, as describedbelow. If the park pawl 22 is pulled out the park position by thepredetermined time t_(C) after the electronic range request signal 28has been received, the method 100 may end. At this point, the pull outof park and garage shift operations are complete.

At step 130, the method 100 may include returning the transmission 14 tothe park operating range and transmitting the indicator signal 70 to theindicator device 68. If the method 100 reaches step 130, the method 100may end. At this point, the transmission 14 has been returned to thepark operating range and the driver has been notified that thetransmission 14 needs to be serviced.

While the best modes for carrying out the invention have been describedin detail, those familiar with the art to which this invention relateswill recognize various alternative designs and embodiments forpracticing the invention within the scope of the appended claims.

1. A vehicle comprising: an engine having an idle speed; a transmissionconnected to the engine and having: a hydraulic pressure source forsupplying a hydraulic fluid at a line pressure; a plurality of clutches,each having a respective clutch pressure; a shift valve that is in fluidcommunication with the hydraulic pressure source and the plurality ofclutches, wherein the shift valve is operable to shift the transmissionto a requested operating range via the plurality of clutches; a parkpawl that is pulled out of a park position to shift the transmission outof a park operating range via one or more of the clutches when thetransmission is requested to shift from the park operating range toanother operating range; and a park sensor configured to determine ifthe park pawl is pulled out of the park position; and an electronictransmission range selection (ETRS) system having a controller and anelectronic range selector device, wherein the electronic range selectordevice is operable to transmit an electronic range request signal to thecontroller to request a shift of the transmission to the requestedoperating range; wherein the controller is programmed to detect a delayin pull out of the park pawl from the park position when thetransmission is requested to shift from the park operating range toanother operating range, and to control an action of the vehicle inresponse to the delay by: receiving the electronic range request signalto shift from the park operating range to another operating range fromthe electronic range selector device; receiving a park pawl positionsignal from the park sensor indicative of the park pawl being pulled outof the park position; determining if pull out of the park pawl from thepark position has not occurred by a predetermined time after the rangerequest signal has been received; and increasing one of the linepressure, the clutch pressures, and the idle speed if pull out of thepark pawl from the park position has not occurred by the predeterminedtime.
 2. The vehicle of claim 1, further comprising a grade sensorconfigured to detect an upgrade and a downgrade relative to the vehicledirection; wherein the controller is programmed to receive a gradesignal from the grade sensor, to determine if the upgrade exceeds apredetermined upgrade and the downgrade exceeds a predetermineddowngrade, and to increase one of the line pressure, the clutchpressures, and the idle speed when one of the predetermined upgrade andthe predetermined downgrade is detected and the electronic range requestsignal to shift from the park operating range to another operating rangeis received from the electronic range selector device.
 3. The vehicle ofclaim 2, further comprising a brake having a brake sensor fordetermining if the brake is applied; wherein the controller isprogrammed to receive a brake application signal from the brake sensorand to increase one of the line pressure, the clutch pressures, and theidle speed and to apply a drive operating range when the electronicrange request signal to shift from the park operating range to the driveoperating range is received from the electronic range selector device,the upgrade exceeds the predetermined upgrade, and the brake is applied;and wherein the controller is programmed to increase one of the linepressure, the clutch pressures, and the idle speed and to apply areverse operating range when the electronic range request signal toshift from the park operating range to the reverse operating range isreceived from the electronic range selector device, the downgradeexceeds the predetermined downgrade, and the brake is applied.
 4. Thevehicle of claim 3, further comprising an indicator device; wherein thecontroller is programmed to return the transmission to the parkoperating range and to transmit an indicator signal to the indicatordevice if pull out of the park pawl from the park position has notoccurred by the predetermined time after increasing one of the linepressure, the clutch pressures, and the idle speed and applying one ofthe drive operating range and the reverse operating range.
 5. Thevehicle of claim 1, wherein the controller is programmed to increase oneof the line pressure, the clutch pressures, and the idle speed when theelectronic range request signal to shift from the park operating rangeto another operating range is received from the electronic rangeselector device and pull out of the park pawl from the park position didnot occur by the predetermined time in a previous shift from the parkoperating range to another operating range.
 6. The vehicle of claim 1,wherein the controller is programmed to return the transmission to thepark operating range if pull out of the park pawl from the park positionhas not occurred by the predetermined time after increasing one of theline pressure, the clutch pressures, and the idle speed.
 7. The vehicleof claim 6, further comprising an indicator device; wherein thecontroller is programmed to transmit an indicator signal to theindicator device if pull out of the park pawl from the park position hasnot occurred by the predetermined time after increasing one of the linepressure, the clutch pressures, and the idle speed.
 8. A system for usein a vehicle having an engine and a transmission, the system comprising:a hydraulic pressure source for supplying a hydraulic fluid at a linepressure; a plurality of clutches, each having a respective clutchpressure; a shift valve that is in fluid communication with thehydraulic pressure source and the plurality of clutches, wherein theshift valve is operable to shift the transmission to a requestedoperating range via the plurality of clutches; a park pawl that ispulled out of a park position to shift the transmission out of a parkoperating range via one or more of the clutches when the transmission isrequested to shift from the park operating range to another operatingrange; a park sensor configured to determine if the park pawl is pulledout of the park position; and an electronic transmission range selection(ETRS) system having a controller and an electronic range selectordevice, wherein the electronic range selector device is operable totransmit an electronic range request signal to the controller to requestthe shift of the transmission to the requested operating range; andwherein the controller is in communication with the electronictransmission range selection system and the park sensor and isprogrammed to: receive the electronic range request signal to shift fromthe park operating range to another operating range from the electronicrange selector device; receive a park pawl position signal from the parksensor indicative of the park pawl being pulled out of the parkposition; determine if pull out of the park pawl from the park positionhas not occurred by a predetermined time after the range request signalhas been received; and increase one of the line pressure, the clutchpressures, and an idle speed of the engine if pull out of the park pawlfrom the park position has not occurred by the predetermined time. 9.The system of claim 8, further comprising a grade sensor configured todetect an upgrade and a downgrade relative to the vehicle direction;wherein the controller is programmed to: receive a grade signal from thegrade sensor; determine if the upgrade exceeds a predetermined upgradeand the downgrade exceeds a predetermined downgrade; and increase one ofthe line pressure, the clutch pressures, and the idle speed when one ofthe predetermined upgrade and the predetermined downgrade is detectedand the electronic range request signal to shift from the park operatingrange to another operating range is received from the electronic rangeselector device.
 10. The system of claim 9, further comprising a brakehaving a brake sensor configured to determine if the brake is applied;wherein the controller is programmed to: receive a brake applicationsignal from the brake sensor; increase one of the line pressure, theclutch pressures, and the engine idle speed and apply a drive operatingrange when the electronic range request signal to shift from the parkoperating range to the drive operating range is received from theelectronic range selector device, the upgrade exceeds the predeterminedupgrade, and the brake is applied; and increase one of the linepressure, the clutch pressures, and the engine idle speed and applying areverse operating range when the electronic range request signal toshift from the park operating range to the reverse operating range isreceived from the electronic range selector device, the downgradeexceeds the predetermined downgrade, and the brake is applied.
 11. Thesystem of claim 10, further comprising an indicator device; wherein thecontroller is programmed to return the transmission to the parkoperating range and transmit an indicator signal to the indicator deviceif pull out of the park pawl from the park position has not occurred bythe predetermined time after increasing one of the line pressure, theclutch pressures, and the engine idle speed and applying one of thedrive operating range and the reverse operating range.
 12. The system ofclaim 8, wherein the controller is programmed to increase one of theline pressures, the clutch pressures, and the engine idle speed when theelectronic range request signal to shift from the park operating rangeto another operating range is received from the electronic rangeselector device and pull out of the park pawl from the park position didnot occur by the predetermined time in a previous shift from the parkoperating range to another operating range.
 13. The system of claim 12,further comprising an indicator device; wherein the controller isprogrammed to return the transmission to the park operating range andtransmit an indicator signal to the indicator device if pull out of thepark pawl from the park position has not occurred by the predeterminedtime after increasing one of the line pressure, the clutch pressures,and the engine idle speed.
 14. The system of claim 8, further comprisingan indicator device; wherein the controller is programmed to return thetransmission to the park operating range and transmit an indicatorsignal to the indicator device if pull out of the park pawl from thepark position has not occurred by the predetermined time afterincreasing one of the line pressure, the clutch pressures, and theengine idle speed.
 15. A method for controlling a vehicle having atransmission and an electronic transmission range selection (ETRS)system in response to a delay in pull out of a park pawl from a parkposition when a shift from a park operating range to another operatingrange is requested, the method comprising: receiving, via a controller,an electronic range request signal from an electronic range selectordevice; sending a pull out of park signal to a shift valve of thetransmission; receiving, via the controller, a park pawl position signalfrom a park sensor; determining, via the controller, if the park pawl isnot pulled out of the park position by a predetermined time after theelectronic range request signal has been received; and executing a firstcontrol action with respect to the vehicle when the park pawl has notbeen pulled out of the park position by the predetermined time after theelectronic range request signal has been received.
 16. The method ofclaim 15, wherein executing the first control action includes increasingone of a line pressure, a clutch pressure, and an engine idle speed. 17.The method of claim 15, further comprising: determining, via thecontroller, if the park pawl was not pulled out of the park position bythe predetermined time after the electronic range request signal wasreceived in a previous shift from the park operating range to anotheroperating range; and executing the first control action with respect tothe vehicle when the park pawl was not pulled out of the park positionby the predetermined time after the electronic range request signal wasreceived in the previous shift.
 18. The method of claim 15, furthercomprising: receiving, via the controller, a grade signal from a gradesensor; determining, via the controller, if an upgrade exceeds apredetermined upgrade and a downgrade exceeds a predetermined downgrade;and executing the first control action with respect to the vehicle ifone of the upgrade exceeds the predetermined upgrade and the downgradeexceeds the predetermined downgrade.
 19. The method of claim 15, furthercomprising: receiving, via the controller, a grade signal from a gradesensor; receiving, via the controller, a brake application signal from abrake application sensor for a brake; determining, via the controller,if an electronic range request signal to shift from the park operatingrange to a drive operating range is received from the electronic rangeselector device, an upgrade exceeds a predetermined upgrade, and thebrake is applied; determining, via the controller, if an electronicrange request signal to shift from the park operating range to a reverseoperating range is received from the electronic range selector device, adowngrade exceeds a predetermined downgrade, and the brake is applied;executing a second control action including increasing one of a linepressure, the clutch pressure, and the engine idle speed and applyingthe drive operating range when the electronic range request signal toshift from the park operating range to the drive operating range isreceived from the electronic range selector device, the upgrade exceedsthe predetermined upgrade, and the brake is applied; and executing athird control action including increasing one of the line pressure, theclutch pressure, and the engine idle speed and applying the reverseoperating range when the electronic range request signal to shift fromthe park operating range to the reverse operating range is received fromthe electronic range selector device, the downgrade exceeds thepredetermined downgrade, and the brake is applied.
 20. The method ofclaim 15, further comprising: returning the transmission to the parkoperating range and transmitting an indicator signal to an indicatordevice if pull out of the park pawl from the park position has notoccurred by the predetermined time after executing the first controlaction.